Home > NOAO: Dr. Arlo Landolt: 55 years of Observing at the National Observatories

NOAO: Dr. Arlo Landolt: 55 years of Observing at the National Observatories

Dr. Landolt is known best for his photometric standard star lists. “Landolt standards” is a term familiar to the entire astronomical community. Astronomers must observe through the Earth’s atmosphere, which, as anyone who watches the weather knows, can vary greatly with the date and location. Therefore, astronomical data must be calibrated; just as your bathroom scale may not reflect the accurate weight measured at your doctor’s office and require a correction, so measurements of stellar brightness must be corrected to keep everyone’s results on the same scale. So astronomers observe the same standard stars, along with their own observations, in order to correct for differences in the sky, the telescope, and the instruments on the telescope. Almost all of Dr. Landolt’s observations have been made at the national observatories: Kitt Peak National Observatory in Arizona, and Cerro Tololo Inter-American Observatory in Chile, where Dr. Landolt was also one of the first observers in March 1965.